Electrically heated crib bottom



Dec. 9, 1952 M. c. RICHARDSON 2,621,279

ELECTRICALLY HEATED CRIB BOTTOM Filed Sept. 21, 1948 2 SHEETS-SHEET l //\/M5/\/ TU MAX c. RKHARDDON fl TTU A/EW Patented Dec. 9, 1952 UNITED STATES PATENT OFFICE ELECTRICALLY HEATED CRIB BOTTOM Max C. Richardson, Portland, O'reg.

Application September 21, 1948, Serial No. 59,402 Claims (01. 219- 19) This invention relates generally to furniture for the use of small children and particularly to the type of childrens furniture known as playbottom on which the child can play both safely and comfortably.

Another object of this invention is to provide a play-pen which can also be conveniently used as a crib which has an electrically warmed bottom and a temperature limiting control for the heating element.

How these and other objects are attained will be apparent on reference to the following description and the accompanying drawings, in which: v

Fig. 1 is a general view in perspective of the childs play-pen and crib of this invention.

Fig. 2 is a fragmentary end elevation of the device of Fig. 1, showing one method of supporting one end of a side panel on a turn button supported. under one end of an end panel.

Fig. 3 is a fragmentary view in perspective showing the under side of the electrically heated bottom of the device of Fig. 1 and the electrical terminal protecting cover and the electrical feeder cord extending therefrom.

Fig. 4 is a somewhat diagrammatic view of the bottom structure of the device of Fig. 1 showing the electric heater embedded therein, together with a schematic showing of the'temperature limiting control for the heater.

Fig. 5 is a fragmentary view in perspective showing how the electric heating wires are placed in the construction of the heated bottom of the device of Fig. 1.

Fig. 6 is a broken sectional View along the line 6-45 of Fig. 3.

.basic conception of the general type of panel used for the bottom of the-device of this invention.

Referring now to the drawings, there is shown in a childs crib having two end leg members I and [2, member ll having downwardly extending legs i3 and it terminating respectively in supporting casters l5 and I6. Similarly, member [2 has downwardly extending legs H and I8 terminating respectively in casters [9 and 20. Hook 2| is swingingly dependent from the crossbar of member H and hook 22 is swingingly dependent from the crossbar of member 12.

End panels, referred to generally as 23 and 24, each have respectively an upper rail 25, 2 6, a lower rail 21, 28 and rods 29 securing each top rail to its respective bottom rail. Upper rails 25 and 26 carry supporting handles 3% and 3| respectively for engagement with hooks 2| and 22.

Side panels referred to generally as 32 and 33, each have respectively an upper rail 34, 35, a lower rail 35, 31 and rods 29 securing each top rail to its respective bottom rail.

Bottom panel 38 is secured to rails 21 and 28 by bolts 39. Turn buttons 49 (of which four would be used but for simplicity only one is shown) are turnably supported by rivet pins 41 on each end of rails 21 and 28. As desired, buttons 40 can be positioned to support side panels 32 and 33 in the upper positions shown by panel 32 in Fig. l, or to allow side panels 32, 333 to slide down to the lower position shown by panel 33 in Fig. l.

Legs 13, Hi, i"! and it are assembled through clearance holes in the ends of the upper and lower rails of the end and side panels as shown in Fi 1.

With end panel handles 3i. and 3! respectively engaging hooks 2| and 22, as shown in Fig. 1, the device becomes a childs crib with either side lowerable as desired.

With end panel handles 38 and 3! respectively disengaged from hooks 2| and 22, all of the side and bottom panels lower to the approximate position shown by panel 33 in Fig. 1 and the device becomes a securely fenced play-pen with the top surface of the lower rails of the side panels on the same elevation and forming an extension of the top surface of the bottom panel as shown in Figs. 1 and 2.

Bottom panel -38 has resistance wire 42 embedded therein. In the drawings a preferred form of bottom 38 is shown as being made of an upper sheet 43 of substantially rigid insulating material such as plywood or pressboard and a lower sheet 44 of substantially rigid insulating material. B. and S., gage No. 26 wire of Driver Harris Co., Number 42 alloy has been found very satisfactory for the resistance element 52. This wire has a relatively high temperature co-efiicient of resistance and a relatively low co-efiicient of expansion. The size and length of wire is selected to give a satisfactory uniform coverage of the panel and a desired heat output.

Bottom panels have been readily and economically produced in the following manner: Lower sheet 44 is perforated according to a pre-determined pattern for the reception of headed insulating pins t and internally threaded, electrically conducting, headed screws 43 and ll. The pins and screws are inserted into the perforations in sheet 44 with the heads standing slightly above the surface of the sheet. One end of wire 52 is attached to one'screw 45 and the wire is then laced over the surface of board 54 as determined .by the placing of pins 55 and the other end of wire 42 is attached to the other screw it. A good insulating glue is then spread over the upper face of sheet 35, or the lower face of sheet 43, or over both these faces, and the sheets are then pressed firmly together and held until the glue has set. Electric cord 53 can then be attached to screws as by attachment screws 49 as shown in Fig. 6. Sheet metal terminal cover 50 is held securely in place by screws 5! mating with screws 41. Guard opening 52 protects cord 48 in its entrance into cover 58. Cover 50 would usually be provided with an insulating paper liner.

In the use of the combination of this invention, it is possible that, on occasion, bedding or other material might so insulate panel 38 that the wire temperature might rise an undesired amount.

To limit the temperature to which the wire s2 is allowed to rise, use is made of the temperature resistance characteristic of the wire, and temperature limiting control 53 is, for convenience, made part of the attachment cord. Limiting control 53 is shown in Fig. 4 to include a supporting case 54 of insulating material with cavities as shown. Supported at one end on case 54, bi-metal element 55 at its other end carries contact member 56 normally contacting contact member 51 carried on bi-metal element 58 supported at one end on member 54. Bi-metal elements 55 and 58 are mounted to respond in the same downward direction to an increase in temperature and are mechanically biased so that in normal operation contact 55 maintains contact with contact 51.

Resistors 59 and 65, also supported on case 5 3, are associated as shown with bi-metals 55 and 58 respectively. Panel heater 432 is thus shown to be connected to power source 5|, 6| through convenience switch 62, resistance 65 and bi-metal contacts 55 and 57. Resistor 59 is shown to be connected across power source 6i, 6!. Resistor 59, of relatively high resistance, and resistor 68, of relatively low resistance, are so selected that, in normal operation when connected as described, resistor 53 supplies to bi-metal 55 substantially the same amount of heat as is supplied to bi-metal 58 by resistor 66. In normal operation, therefore, bi-metals 55 and 58 move together under the influence of the heat supplied them and contacts 55, 51 remain in contact. However, as the temperature of wire 52 rises, its resistance increases and, at a pre-determined temperature of wire42, the increased resistance of wire t2 will the stated and other objects of this invention are attained,

I claim:

1. An electrically heated bottom member for a childs play-pen and crib comprising a lower sheet of substantially rigid insulating material, an upper sheet of substantially rigid insulating material, a quantity of insulating glue, a length of resistance wire, a plurality of headed insulating pins and a plurality of headed and internally threaded electrically conducting screws, said lower sheet being perforated to a pre-determined pattern with holes of a pre-determined size, said pins being inserted from one side of said lower sheet into certain of said holes in a pre-determined pattern, said screws being inserted from said one side of said lower sheet into certain other of said holes in a pre-determined pattern, said wire being laid on said one side of said lower sheet in a pattern determined by said pins, said wire being terminated at certain of said screws, said upper sheet being positioned closely adjacent said one side of said lower sheet, and said glue filling all of the space between said two sheets and surrounding said wire and the headed ends of said pins and said screws.

2. The method of constructing an electrically heated bottom member for a childs play-pen and crib comprising a lower sheet of substantially rigid insulating material, an upper sheet of substantially rigid insulating material, a length of resistance wire, a plurality of headed insulating pins, a plurality of headed and internally threaded electrically conducting screws, and a quantity of insulating glue, which includes perforating said lower sheet to a pre-determined pattern with holes of a pre-determined size, inserting said pins into certain of said holes in a predetermined pattern, inserting said screws into certain others of said holes in a pre-determined pattern, said pins and said screws having their headed ends extending from said holes above the top surface of said lower sheet, laying said wire on said top surface of said lower sheet in a pattern determined by said pins and certain of said screws, terminating said wire at said certain screws, spreading said glue over said top side of said lower sheet, said wire, and the exposed heads of said pins and said screws, pressing said upper sheet firmly against said glue covered top surface of said lower sheet and holding said sheets in a firmly pressed together condition until said glue has set.

3. The method of claim 2 but with the variation that the glue is first applied to the under surface of said top sheet rather than to the upper surface of said lower sheet.

4. The method of claim 2 but with the variation that the glue is applied to both the under surface of the upper sheet and the upper surface of said lower sheet.

MAX C. RICHARDSON.

(References on following page) 5 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Jamieson et a1 July 4, 1911 Daugherty May 27, 1930 Starr May 5, 1931 Myron Jan. 5, 1932 Hare Nov. 8, 1932 Gebhard Feb. 21, 1933 Wiggins 1- May 1, 1934 Anderson July 30, 1935 Number 6 Name Date Hilton Dec. 15, 1936 Brousseau Nov. 14, 1939 Brown Nov. 5, 1940 Klopfer et a1. Sept. 16, 1941 Kearsley Aug. 1, 1944 Reimers July 2, 1946 MacKendrick July 1, 1947 Raymond Sept. 30, 1947 Williams July 5, 1949 Bourdon July 26, 1949 Crise Mar. 7, 1950 Richardson Sept. 5, 1950 

